2 x U2713H & 1 x U2711. U2711 not working with MST.

* Dell monitor model? 2 x U2713H, i x U2711
* What is the revision number (A00, A01, etc.) ? 2 x A07, 1 x A08
* What is the monitor 20 digit alpha-numeric serial number? CN0C6F0K74261441062L, CN0C6F0K7426143K0K6L, CN0D970T742611970A7L
* What specific computer model, desktop/laptop? White Box, Intel 950
* What operating system? Windows 8.1 64 Bit
* What video card? AMD sapphire 290
* What video out ports are available on the video card? 2 x DVI, 1 x HDMI, 1 x DP
* What video out port are you using from the video card to what video in port on the monitor? DP only connected to U2713H Mini-DP.  DP out to U2713H to Mini-DP. DP out to U2711 DP
* What cable are you using to attach the video card to the monitor? Dell U2713H cable, Dell U2713H cable. DP cable that came with video card and a shop bought comsol. (Tested both)
* Are you using the Dell supplied cable? Yes, Yes, No DP cable came with Monitor.

I have just bought 2 x U2713H to add to my existing U2711. I am setting it up to daisy chain via MST in the following order. PC to U2713H to U 2713H to U2711. I bought these monitors to cut down on cable clutter as I wish to daisy chain them all.

The new U 2713H work fine but I am unable to get the U2711 working with Windows.

Actions tried/setting confirmed

*U2713H Monitors set to displayport1.2. Not other setting change from factory

* multiple DP cables to the U2711 tried

Additional Info.

*The U2711 has been working for years with a DP cable

*When booting, The U2711 shows bios post

*When attempting to activate in windows, I receive the error " the display setting could not be saved. Try a different combination of display settings)

*Second monitor has a Dell soundbar connected

*AMD Catalyst Control centre does not see the third monitor, reports total bandwidth 20.76Gbps,and bandwidth utilization of 86% (Biggest concern here :emotion-1: ) 

* latest AMD driver in use (Not beta)